Katy Perry is giving fans a sneak peek at her new album Prism one track at a time.  After releasing her second teaser track, "Dark Horse," on Tuesday, the singer has now announced that yet another track is coming: "Walking on Air" will make its debut September 30.

"Mark your calendars for the next #PRISMPREVIEW on SEPT 30 when you can hear/have the new song 'WALKING ON AIR' before the record hits," she tweeted.  However, she clarified, as she did with "Dark Horse," that neither of these songs are the actual follow-up to "Roar."

"Remember these are NOT singles, just tastes to enjoy!" she wrote. "#ROAR is still ROARING & 2nd single from PRISM will not be announced for some time...But don't you worry... I promise you'll like it!"

"Dark Horse" features rapper Juicy J, a member of the Oscar-winning rap group Three 6 Mafia.  "Boy you should know what you're falling for/Baby do you dare to do this?/Cause I'm coming at you like a dark horse," Katy sings to a male suitor. "Are you ready for a perfect storm/'Cause once you're mine/there's no going back."